An automated, battery-powered device designed to continuously record electroencephalographic signals in ambulatory patients for periods usually from 24 to 72 hours to assess a variety of neurological conditions (e.g., epilepsy) and psychiatric disorders. It typically includes a small cassette tape recorder or a digital medium (no moving parts) with appropriate signal amplifiers worn by the patient, and a set of scalp electrodes that are placed on the cranium of the patient. The resulting electroencephalogram (EEG) is typically analysed in an electroencephalographic analyser.